KR930002532B1 - Aluminium base alloy for use as sliding material superior in fatigue resistance & anti-seizure property - Google Patents

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Description

Aluminum base alloy for sliding materials with excellent fatigue resistance and arsenic resistance

1 is a table showing the fatigue test results for each of the composite bearing of the prior art and the present invention.

Figure 2 (a) and (b) is a block diagram showing the basic process for manufacturing each of the composite bearing according to the present invention.

3 is a partial cross-sectional view of the composite bearing photographed at a magnification of 100, showing the microstructure of the composite bearing produced by the preferred embodiment of the present invention.

The present invention relates to a sliding aluminum base alloy having excellent fatigue resistance and anti-seizure. In particular, the present invention is applied to half bearings, cylinder bushes, flange bearings, thrust washers, etc. of sliding bearings. The present invention relates to an aluminum base alloy for sliding material having excellent fatigue resistance and arsenic resistance suitable for various industrial fields such as machinery.

As prior art related to the present invention, for example, the specifications of West German Patent Nos. 1,533,413 and 1,558,696, US Patent No. 4,170,469 and British Patent 1,593,006 are disclosed. In these prior arts, each alloy composition is composed of 0.1-10% by weight of Zn, 0.1-20% by weight of Si, 0.1-10% by weight of Cu, and 0.1-10% by weight of Pb, and optionally Ni, Bi and Mg. At least one component in the group consists of 0.1-7% by weight of additives, with the balance being Al-based alloys for bearing materials. Mostly, internal combustion engines for automobiles have made rapid progress and have high speed and high load. Therefore, even when the Al-based alloy of the prior art is used as a sliding material, especially as a bearing material for a high-speed internal combustion engine, the lubricating oil film becomes thin, and as a result, there is a disadvantage that the non-baking resistance and fatigue resistance are reduced. Therefore, an object of the present invention is to provide an Al-based alloy used as a sliding material, which is excellent in fatigue resistance and non-baking resistance to eliminate the defects of the conventional Al-based alloy for use as a sliding material.

Al base alloy which can achieve the said objective is four types of Al base alloys.

(1) Fatigue and non-baking resistance of 1-10% by weight of Zn, 1-15% by weight of Si, 0.1-5% by weight of Cu, 0.1-5% by weight of Pb, 0.005-0.5% by weight of Sr, and the balance being substantially Al. This excellent Al-based alloy for sliding materials.

(2) Zn 1-10% by weight, Si 1-15% by weight, Cu 0.1-5% by weight, Pb 0.1-5% by weight, Sr 0.005-0.5% by weight as essential ingredients and as an optional additive ingredient A group An Al-based alloy for a sliding material having excellent fatigue resistance and non-baking resistance, in which 0.05-5% by weight of the additive component and the balance of the minimum components selected from 0.05-5% by weight of Mg and 0.05-5% by weight of Ni are substantially Al.

(3) Zn 1-10% by weight, Si 1-15% by weight, 0.1-5% by weight of Cu, 0.1-5% by weight of Pb and 0.005-0.5% by weight of Sr are essential components, and Mn 0.05-2% by weight Al group for a sliding material having at least one component selected from the group B consisting of%, V 0.05-2% by weight and Cr 0.05-2% by weight, having a total of 0.05-2% by weight and having a balance of Al. alloy.

(4) Zn 1-10% by weight, Si 1-15% by weight, 0.1-5% by weight Cu, 0.1-5% by weight Pb, 0.005-0.5% by weight Sr as essential components, Mg 0.05-5% by weight and At least one component selected from group A consisting of 0.05-5% by weight of Ni with 0.05-5% by weight of additives, Mn 0.05-2% by weight, V 0.05-2% by weight and Cr 0.05-2% by weight At least one component selected from the group B consisting of an additive component having a total of 0.05-2% by weight, and a total content of the above-mentioned components of the group A and B in the range of 0.05-4% by weight, with the balance being Al; Al-based alloy for sliding materials with excellent sintering properties.

Next, the reason for limiting each component of the Al-based alloy for sliding material having excellent fatigue resistance and arsenic resistance of the present invention to the claims (1)-(4) (reason of upper and lower limits of the content of each alloy component) The action of and will be described below.

(1) Si: 1 to 15% by weight

(a) When fine particles of Si with high hardness (about 600 Hv) exist as dots in the matrix of Al, only the Al matrix having a smooth surface is worn out, and the surface of the alloy becomes irregularly shaped as seen under a microscope. Thus, the convex silicon particles retain their non-adhesiveness to withstand high load loads while the recess serves as an oil reservoir. The alloy thus withstands high loads, thin oil films and contact with metals.

(b) The finely present Si particles function to wear the corners, burrs, and the like on the A side of the coupling shaft to improve non-baking. In this case, when the Si particles are rough, there is a risk that the Si particles themselves fall off as well as locally excessive wear of the shaft. This requires a limit or control of its size.

(c) In the case of instantaneous metal contact between the Al matrix and the coupling shaft, the fluidity and bake of the alloy bearing are prevented due to the non-flowability of the Al matrix with Si as the core and the non-adhesion of silicon in the alloy surface.

(d) When the content of silicon is 1% or less, the alloy does not exhibit the advantageous properties and wear resistance shown in the above (a), (b) and (c). When the content of silicon exceeds 15%, the alloy is fragile, the impact fatigue strength is weakened, and the toughness is insufficient. Therefore, the plasticity is low in the manufacture of rolling and extrusion.

Preferably the silicon content is 3 to 8% by weight.

(2) Zn: 1 to 10% by weight

(a) Zn is in a solid solution state in the Al matrix and the weldability is lowered by changing the space lattice gap.

(b) Zn is preferentially oxidized compared to Al to remove the harmfulness of the solid Al oxide film.

(c) Zn increases the affinity of the lubricant with the alloy.

(d) When the content of Zn is 1% by weight or less, the alloy has low non-baking resistance and wear resistance. If the content of Zn exceeds 10% by weight, the alloy bearings are prone to stress corrosion cracking, and at the same time, the toughness is weakened. In addition, when a soft material such as an overlay is applied to the surface of the alloy, it is difficult to make an electrodeposition of, for example, an electroplating layer. In addition, this case adversely affects the adhesion of the pressure welding. Preferably Zn content is the range of 2-8 weight%.

(3) Cu: 0.1 to 5% by weight

(a) The addition of Cu is very effective in increasing the strength of the Al matrix and increasing the fatigue resistance. However, if the hardness of the alloy is too large, there is a problem of affinity. The same applies to Ni.

(b) If the content of Cu is less than 0.1% by weight, there is no significant characteristic by addition of Cu. If the content of Cu is more than 5% by weight, the alloy has a very high hardness resulting in a decrease in affinity and toughness. Preferably the Cu content is in the range of 0.5 to 2% by weight,

(4) Pb: 0.1 to 5% by weight

The addition of Pb increases the non-baking and workability of the alloy. However, when the Pb content is 0.1% by weight or less, the addition of Pb has no significant effect. When the Pb content is 5% by weight or more, it is very difficult to obtain a uniform dispersion of Pb in the Al matrix and adversely affect the strength of the alloy.

Preferably the Pb content is between 0.5% and 3% by weight.

(5) Sr: 0.005 to 0.5 wt%

(a) Sr has the effect of finely crystallizing the particles of silicon.

(b) Sr improves the mechanical properties, in particular the elongation of the alloy.

(c) If Sr is less than 0.005% by weight, the addition of Sr is not important, and if Sr is more than 0.5% by weight, the ductility of the alloy is reduced.

Preferably the Sr content is between 0.01% and 0.1% by weight.

(6) Mg and / or Ni selected from Buty as group A: 0.05 to 5% by weight (a) Mg and / or Ni is in a solid solution state in the Al matrix or precipitates in the form of a metal compound to increase its fatigue strength.

(b) When Mg and / or Ni is 0.05% by weight or less, there is no practical effect by the addition of Mg and / or Ni. When Mg and / or Ni is 5% by weight or more, the alloy has an excessively high hardness and therefore has affinity. Low and toughness decreases.

Preferably the content of Mg and / or Ni is 0.1 to 3% by weight.

(7) at least one component selected from the group B consisting of Mn, V and Cr: 0.05 to 2% by weight

(a) This component is dissolved in the Al matrix or precipitated in the form of a metal compound to improve the mechanical properties of the alloy at high temperatures.

When content of (b) component is 0.05 weight% or less, the addition does not have the actual characteristic. If it is 2% by weight or more, the particles of the metal compound become rough because the alloy is brittle.

(8) Total content of components selected from Group A and Group B: 0.05 to 4% by weight

The component (a) is in solid solution in the Al matrix or precipitates in the form of a metal compound to improve fatigue resistance.

(b) If the total content is less than 0.05% by weight, there is practically no effect. If the total content is more than 4% by weight, the alloy is too high in hardness and therefore has low affinity and reduced toughness.

Preferably the total content is in the range of 0.1% to 3% by weight.

Hereinafter, the present invention will be described in more detail with reference to the following examples.

Example 1

As shown in Table 2, alloy Nos. 16 to 30 and Comparative Alloy Nos. 1 to 15 of the present invention were cast into rods having a diameter of 10 inches (25.4 cm) at temperatures of 750 ° C to 850 ° C, respectively. Each rod is annealed at a temperature of 400 ° C. to 500 ° C. and then extruded into the residue at an extrusion ratio of 35 to 45. The residue is annealed at a temperature of 350 ° C. to 450 ° C. and then rolled to obtain a rolled material. Thereafter, the rolled material is annealed at a temperature of 300 ° C. to 400 ° C., and then press welded to a steel backing under pressure at a reduction ratio of 30 to 50% to obtain a bimetal member. The bimetal member is annealed at a temperature of 300 to 400 ° C. and then calcined into a semicircular shape. It is plated with a Pb-10% Sn alloy with a thickness of 10-20 microns to provide an overlay on the inner surface of this semi-circular plastic member. Thus, semicircular composite bearings are obtained. The manufacturing process of this composite bearing is shown in FIG. 2 (a) while some cross sections of the composite bearing are shown in FIG.

The semicircular composite bearing was subjected to the fatigue test and the baking test under the conditions shown in Table 1, and the fatigue test results are shown in FIG. 1, and the results of the baking test are shown in Table 3. In addition, the bimetallic member is tested for mechanical properties prior to plastic working in a semicircular shape and the results are shown in Table 2. Among these mechanical properties, the bond strength is tested by the following method. That is, each bimetal member having a width of B (mm) is prepared, and then two parallel grooves are formed in the bimetal member with a gap of L (mm), and one groove extends from the outer surface of the bearing alloy layer to the adhesion boundary surface and the other one. Grooves extend from the outer surface of the reinforcement layer to the adhesive interface. Then, on the opposite side, each end of the two specimens is tensioned in the opposite direction, and then the tensile strength measured when the steel reinforcement layer is peeled off the bearing alloy layer is divided by the adhesion area of BxL (mm2) to determine the bond strength.

Example 2

Each bimetal member having the same shape as in Example 1 was prepared, and each composite bearing having the same shape as in Example 1 was prepared from the bimetal member in the process of FIG. 2 (b) under the same conditions, and the process was carried out in the second ( The same alloy as in Example 1 shown in a) is used, but instead of the post-extrusion extrusion and annealing shown in FIG. 2 (a), a rolling process and annealing of 300 ° C. to 400 ° C. is used, respectively. The same test as in Example 1 was carried out on the thus obtained bimetallic member and the composite bearing, and the result was substantially the same as in Example 1. In Examples 1 and 2, an intermediate Ni plating layer having a thickness of 1.5 microns was provided between the bearing alloy layer and the overlay to obtain adhesive strength. Moreover, this intermediate plating layer can be provided using Cu or Cu alloy instead of Ni. In addition, in Examples 1 and 2, the steel reinforcement layer and the bearing alloy layer are directly pressed against each other. However, it is known that the adhesion strength of the Ni plating layer or Al thin film interposed therebetween greatly improves the adhesive strength.

The present invention has the following excellent effects.

(A) The alloy of the present invention improves fatigue resistance and arsenic resistance as compared with conventional alloys (see FIG. 1 and Table 3).

(B) In particular, non-plasticity (non-flowable light non-adhesion) is remarkably due to the respective action of the Al matrix in which Zn is in solid solution, Si is crystallized and dispersed with the addition of Sr, and Pb is dispersed in the Al matrix. Is improved.

(C) In particular, in the case of the present invention, the Si grains are limited to 15 microns or less by microaddition of Sr in consideration of the coarse Si particles damaging the bonding axis during use, and the non-sintering properties are higher than those of conventional alloys. It can be greatly improved.

TABLE 1a

TABLE 1b

TABLE 2

TABLE 3

Claims (4)

Fatigue resistance and arsenic, characterized in that Zn 1-10% by weight, Si 1-15%, Cu 0.1-5%, Pb 0.1-5%, Sr 0.005-0.5% by weight and the balance substantially consists of Al Al base alloy for sliding material with excellent buoyancy. Zn 1-10% by weight, Si 1-15% by weight, 0.1-5% by weight Cu, 0.1-5% by weight Pb, 0.005-0.5% by weight Sr, the Mg 0.05-5% by weight and Ni 0.05 Al-based alloy for sliding material having excellent fatigue resistance and non-baking resistance, characterized in that the minimum component selected from the group A consisting of -5% by weight is 0.05-5% by weight in total, and the balance is substantially Al. . Zn 1-10% by weight, Si 1-15% by weight, Cu 0.1-5% by weight, Pb 0.1-5% by weight, Sr 0.005-0.5% by weight as essential ingredients, Mn 0.05-2% by weight and V 0.05 At least one component selected from the group B consisting of -2% by weight and 0.05-2% by weight of Cr, and has an excellent fatigue resistance and non-baking resistance, characterized in that the total of 0.05-2% by weight of the additive component and the balance substantially consists of Al. Al-based alloy for sliding materials. Zn 1-10 wt%, Si 1-15 wt%, Cu 0.1-5 wt%, Pb 0.1-5 wt%, Sr 0.005-0.5 wt% as essential ingredients, Mg 0.05-5 wt% and Ni 0.05- At least one component selected from the group A consisting of 5% by weight of 0.05-5% by weight of the additive, Mn 0.05-2% by weight, V 0.05-2% by weight, and 0.05-2% by weight of Cr The Al-based alloy for sliding material having excellent fatigue resistance and non-baking resistance, characterized in that the total content of the above-mentioned components of Group A and Group B is 0.05 to 4% by weight, and the balance is made of Al.

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